Curtain walls are used as outer coverings for standing structures such as buildings and skyscrapers. Curtain walls are generally non-load bearing structures and used primarily for providing protection from the weather and other external elements such as noise and sound. In particular, curtain walls are designed to resist air and water infiltration, and to accommodate building movements induced by thermal changes, wind and seismic forces acting on the building structure. In building construction, the use of structural steel and reinforced concrete frames in place of load-bearing masonry has resulted in the use of relatively small columns for supporting large loads. Exterior walls, no longer needed for providing structural support, have become lighter and more open, allowing for a greater use of glass in the exterior façade than was possible in the load-bearing masonry walls of the past.
A curtain wall is generally constructed from a plurality of individual members such as frames, doors, panels, windows and the like, which are assembled together and anchored to the building structure. The curtain wall does not carry any dead load weight besides its own dead load weight, and is adapted to convey any horizontal wind loads that are incident upon it to the building structure through connections to the primary structure of the building. Curtain walls are typically constructed with a metal frame (e.g., aluminum or steel). The frame is usually filled with an infill panel such as glass. The infill panel provides the building with an aesthetically pleasing appearance and other benefits including daylighting, waterproofing, thermal and acoustic insulation.
There is a need for a curtain wall unit adapted for forming a curtain wall that is environmentally friendly, and simple and cost-effective to fabricate and implement, while broadening the flexibility and range of aesthetic designs beyond those typically associated with extruded metal construction. There is a need for a curtain wall unit that exhibits desirable characteristics including high compressive strength, excellent ductility, and high tensile strength. There is a further need for a curtain wall unit that possesses improved durability, exceptional fireproof ratings, excellent blast resistance, corrosion resistance, and water impermeability desirable in a curtain wall.